About 1-1.5 million people in US are infected with human immunodeficiency virus (HIV). Of these, 20-30% will develop acquired immune deficiency syndrome (AIDS). One half to one third of AIDS patients will have an HIV related neurological disorder (AIDS-dementia complex) that occurs following relatively long latency periods. Factors related to virus reactivation are unknown. The proposed studies seek to define the potential contribution of the herpesviruses to the development of the HIV induced AIDS-dementia complex. The working hypothesis is that trans-activating herpesvirus genes activate HIV expression, possibly through the contribution of cellular factors. HIV-LTR/CAT and HIV-LTR-gag-env constructs will be used in transient expression assays and to establish permanent lines of neural (astrocytes, oligodendrocytes, glioma lines) and monocytic (primary and U937 cells) cells. Transfection with HSV, CMV and EBV trans-activating genes will be done to define: (i) the potential homeostatic balance that may result from the concerted action (on HIV-LTR) of respectively positive and negative controls provided by the trans- activating genes, (ii) the sequences within HIV-LTR that contain specific recognition sites for HIV activation (or down-regulation), (iii) the identification and potential contribution of cellular regulatory genes, and (iv) the effect of regulatory genes on production of AST-CF, an astrocyte-produced factor that is cytotoxic for oligodendrocytes (in collaboration with Dr. Shin). Activation will be respectively determined by CAT enzyme and RNA (S1 nuclease) assays, and FA staining with MAbs to p24 and gp120 and Northern blot assays with gag and env probes. The role of DNA hypomethylation in HIV activation will be determined. The HIV-LTR sequences that respond to trans-activation will be determined with deletion mutants and their ability to impart responsiveness upon s previously non-responsive promoter will be established. Gel retardation assays will be used to define the contribution of cellular transcription factors. Cytokines generated by herpesvirus stimulated T cells will be studied for their ability to activate HIV-LTR and induce expression of the c-fos regulatory gene. The role, if any, of c-fos in HIV-LTR activation will be determined with an antisense c-fos construct. By stressing regulatory aspects, these studies should provide information crucial to the understanding of the HIV/herpesvirus interaction in AIDS-dementia complex thereby contributing to the development of effective therapeutic and/or preventive modalities.